DESCRIPTION: (Applicant's Abstract) Since the virtual eradication of poliomyelitis, the Guillain-Barre' Syndrome (GBS) is the most common cause of acute flaccid paralysis. It has been assumed that GBS is an immunologically medicated disease, but the etiologies and mechanisms have not been established. In Northern China, GBS occurs in two forms: An axonal form, Acute Motor Axonal Neuropathy (AMAN), and Acute Inflammatory Demyelinative Polyneuropathy (AIDP). The AMAN form occurs in summer epidemics, affecting hundreds, if not thousands of children and young adults. The AIDP, as in Europe and North America, occurs throughout the year in China. Both forms, but particularly the AMAN cases, are associated with a preceding infection with Campylobacter jejuni. The hypothesis being tested is that specific strains of C.jejuni are associated with either AMAN or AIDP in susceptible individuals. The unique concentration of cases in China allows the rapid testing of this hypothesis. We are identifying the cases of AIDP and AMAN by clinical and electrodiagnostic criteria. With autopsy material we have clarified the specific pathologies of AIDP and AMAN. C.jejuni association is confirmed by serological studies, bacterial isolation, and production of an animal model. Host factors are considered by determining HLA alleles by DNA techniques. The information gained from the study of Chinese cases has application to understanding the various forms of GBS that occur in the United States and the rest of the world.